A number of reliable outdoor navigation systems are widely available. These systems typically rely on the deployment of a global satellite network such as, for example, the Global Navigation Satellite System (GNSS), the Global Positioning System (GPS) and the GALILEO satellite system. These satellites transmit signals that provide accurate timing information as well as the location of the satellite. A ground receiver that has a line-of-sight to the satellites may pick up these signals from three or more satellites and estimate its own position by calculating the distance to each of the satellites based on the travel time of the signal from the satellite to the ground receiver and further based on the known locations of the satellites. Indoor environments, however, generally limit the reception of such line-of-sight satellite signals rendering GPS-based systems unworkable. One solution to the indoor navigation problem is based on a deployment of transceivers or responders throughout the indoor structure, such as, for example stationary Wireless Fidelity (Wi-Fi) stations or access points (APs) that conform to the IEEE 802.11 standard. A mobile station, for example a hand held user device, may then estimate its location based on signal Time-of-Flight (ToF) measurements with respect to a number of these fixed stations, using a technique known as the 802.11 Fine Time Measurements (FTM) procedure. The user's mobile equipment performs the FTM procedure with one or more stationary FTM capable stations or APs (e.g., FTM Responders) and estimates the distance to each FTM Responder, to calculate its location relative to each of the Responders' locations. There are a number of non-trivial issues associated with respect to managing FTM responders.
Although the following Detailed Description will proceed with reference being made to illustrative embodiments, many alternatives, modifications, and variations thereof will be apparent to those skilled in the art.